formats/png/test_utils.h

// Copyright 2026 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//

#ifndef THIRD_PARTY_CREDENTIO_FORMATS_PNG_TEST_UTILS_H_
#define THIRD_PARTY_CREDENTIO_FORMATS_PNG_TEST_UTILS_H_

#include <cstdint>
#include <optional>
#include <string>

#include "absl/status/status.h"
#include "absl/status/statusor.h"
#include "absl/types/span.h"
#include "riegeli/bytes/writer.h"

namespace credentio {

// A PNG chunk.
struct Chunk {
  // Chunk type (e.g., 'IDAT' or 'caBX').
  uint32_t type;
  std::string payload;
  // If set, the CRC will be set to this value.
  std::optional<uint32_t> crc = std::nullopt;
};

// Creates a PNG image from the given chunks.
absl::StatusOr<std::string> CreatePng(absl::Span<const Chunk> chunks,
                                      bool add_header = true,
                                      bool add_end = true);

// Lower-level functions.
absl::Status WritePngHeader(riegeli::Writer& buffer);
absl::Status WritePngChunk(riegeli::Writer& buffer, const Chunk& chunk);
absl::Status WritePngEnd(riegeli::Writer& buffer);

}  // namespace credentio

#endif  // THIRD_PARTY_CREDENTIO_FORMATS_PNG_TEST_UTILS_H_